The mechanism of Na(+)-dependent transport of L-carnitine via the carnitine/organic cation transporter OCTN2 and the subcellular localization of OCTN2 in kidney were studied. Using plasma membrane vesicles prepared from HEK293 cells that were stably transfected with human OCTN2, transport of L-carnitine via human OCTN2 was characterized. Uptake of L-[(3)H]carnitine by the OCTN2-expressing membrane vesicles was significantly increased in the presence of an inwardly directed Na(+) gradient, with an overshoot, while such transient uphill transport was not observed in membrane vesicles from cells that were mock transfected with expression vector pcDNA3 alone. The uptake of L-[(3)H]carnitine was specifically dependent on Na(+) and the osmolarity effect showed that Na(+) significantly influenced the transport rather than the binding. Changes of inorganic anions in the extravesicular medium and of membrane potential by valinomycin altered the initial uptake activity of L-carnitine by OCTN2. In addition, the fluxes of L-carnitine and Na(+) were coupled with 1:1 stoichiometry. Accordingly, it was clarified that Na(+) is coupled with flux of L-carnitine and the flux is an electrogenic process. Furthermore, OCTN2 was localized on the apical membrane of renal tubular epithelial cells. These results clarified that OCTN2 is important for the concentrative reabsorption of L-carnitine after glomerular filtration in the kidney.

These results suggest that VEGF plays an important role in lymph node metastasis through induction of angiogenesis in NPCs.

Integrin avf35 promotes FG carcinoma cell adhesion to vitronectin yet requires protein kinase C (PKC) activation for migration on this ligand. Here we report that this PKCdependent cell motility event requires NF-KB-dependent transcription. Specifically, a component within nuclear extracts prepared from PKC-stimulated FG cells exhibited a significant increase in binding activity to a synthetic oligonucleotide containing a consensus KB sequence. These nuclear DNA-binding complexes were shown to be comprised of p65 and p50 NF-KB/rel family members and appeared functionally active because they promoted transcription of a reporter construct containing a KB site. The NF-KB activation event was directly linked to the av,35 motility response because the NF-KB-binding oligonucleotide, when introduced into FG cells, inhibited cell migration on vitronectin but not on collagen and had no effect on cell adhesion to either ligand. These results suggest that the detected DNA-binding complexes interact with KB transcriptional elements to regulate gene expression required for avp35-dependent cell motility on vitronectin. INTRODUCTION Regulation of cell migration is a critical factor during tissue remodeling associated with angiogenesis, embryogenesis, inflammation, and wound healing (Albelda and Buck, 1990). Upon neoplastic transformation, cells acquire a migratory phenotype that facilitates their ability to metastasize. Integrins are cell surface receptors that mediate cell-matrix interactions critical for cell motility (Ruoslahti, 1991;Hynes, 1992;Leavesley et al., 1992Leavesley et al., , 1993Klemke et al., 1994). Although integrin-mediated cell adhesion is necessary for migration, it is not always sufficient. For example, recent studies have shown that integrin-dependent cell motility, but not attachment, requires the presence of exogenous growth factors Matthay et al., 1993;Klemke et al., 1994), suggesting that cell motility involves activation events not required for adhesion.t Corresponding author.FG pancreatic carcinoma cells attach to vitronectin utilizing integrin av,85, yet are unable to migrate on this ligand even though they attach and migrate on collagen in an a2f31 integrin-dependent manner (Leavesley et al., 1992). These findings indicate that FG cell migration on collagen is constitutive whereas av135-dependent migration on vitronectin requires agonist activation. However, we recently showed that FG cells can be induced to migrate on vitronectin in the presence of soluble growth factors, such as epidermal growth factor and insulin-like growth factor, which act by stimulating a PKC-dependent signaling pathway (Klemke et al., 1994).PKC is known to activate the adhesive properties of some cells by enhancing the affinity of their cell surface integrins (Shattil and Brass, 1987;Hibbs et al., 1991;Valmu et al., 1991;Wilkins et al., 1991; MartinThouvenin et al., 1992). In addition, PKC potentiates signaling events leading to integrin-dependent cell spreading and motility (Vuori and Ruoslahti, 1993;Klemke et al., 1994...

The homogenates of amyloid-laden spleens prepared from CBA mice were analysed by SDS-PAGE and immunoblotting employing rat anti-murine monoclonal antibody, MSA 4-26. The results showed that the precursor of amyloid A protein (AA), serum amyloid A protein 2 (SAA2), and SAA intermediates with molecular weights of 10,000, 9000, and 8000 were contained in amyloid-laden tissues. The experiment using sonicated spleen cells and acute phase murine sera showed a delay in the degradation rate of SAA2 on cell fragments and the remains of SAA1 in supernatants. This result can explain disappearance of SAA2 from the murine serum during amyloidogenesis in vivo.

Adenomatous hyperplasia, defined as a sizable parenchymal nodule in cirrhosis, was examined morphologically. Ninety-seven nodules of adenomatous hyperplasia were obtained from 47 cirrhotic livers and were divided into 'ordinary' (44 nodules) and 'atypical' (53 nodules) types. The former consisted of hepatocytes similar to those of the surrounding liver, and showed regularly distributed portal tracts. The latter type was composed of hepatocytes showing nuclear atypia, relative to the surrounding liver, and showed irregular or sparse portal tracts. Atypical nodules were histologically heterogeneous, possessing areas of normo-trabecular, compact, pseudoglandular and/or scirrhous patterns. Several cytological changes, such as clear cell change, small or large cell change and fatty change, were intermingled variably within a given nodule. Atypical nodules showed expansive and/or replacing growth into the surrounding liver. Atypical hepatocytes also infiltrated into the fibrous septa and portal tracts. Foci of overt hepatocellular carcinoma were found in 11 of the 53 atypical nodules. These findings suggest that ordinary adenomatous hyperplasia may be a large-sized regenerative nodule, while atypical adenomatous hyperplasia may be a hepatocellular neoplasm, a peculiar form of low-grade hepatocellular carcinoma or borderline lesion, in which overt hepatocellular carcinoma is likely to evolve through multiple steps.